<template>
  <div class="app-container">
    <h2 style="text-align: center;">发布新课程</h2>
    <el-steps :active="1" process-status="wait" align-center style="margin-bottom: 40px;">
      <el-step title="填写课程基本信息"/>
      <el-step title="创建课程大纲"/>
      <el-step title="最终发布"/>
    </el-steps>
    <el-form label-width="120px">
        <el-form-item label="课程标题">
             <el-input v-model="courseInfo.title" placeholder=" 示例：机器学习项目课：从基础到搭建项目视频课程。专业名称注意大小写"/>
        </el-form-item>
        <!-- 所属分类 TODO -->
        <el-form-item label="课程分类">
        <el-select
            v-model="courseInfo.subjectParentId"
            placeholder="一级分类" @change="subjectLevelOnChanged">
            <el-option
            v-for="subject in subjectOneList"
            :key="subject.id"
            :label="subject.title"
            :value="subject.id"/>
        </el-select>
        <!-- 二级分类 -->
        <el-select
            v-model="courseInfo.subjectId"
            placeholder="二级分类">
            <el-option
            v-for="subject in subjectTwoList"
            :key="subject.id"
            :label="subject.title"
            :value="subject.id"/>
        </el-select>
        </el-form-item>
        
        <!-- 课程讲师 TODO -->
        <el-form-item label="课程讲师">
            <el-select
                v-model="courseInfo.teacherId"
                placeholder="请选择">
                <el-option
                v-for="teacher in teacherList"
                :key="teacher.id"
                :label="teacher.name"
                :value="teacher.id"/>
            </el-select>
        </el-form-item>

        <el-form-item label="总课时">
            <el-input-number :min="0" v-model="courseInfo.lessonNum" controls-position="right" placeholder="请填写课程的总课时数"/>
        </el-form-item>
        <!-- 课程简介  -->
        <el-form-item label="课程简介">
            <tinymce :height="300" v-model="courseInfo.description"/>
        </el-form-item>

        <!-- 课程封面-->
        <el-form-item label="课程封面">
            <el-upload
                :show-file-list="false"
                :on-success="handleAvatarSuccess"
                :before-upload="beforeAvatarUpload"
                :action="BASE_API+'/eduoss/fileoss/upload'"
                class="avatar-uploader">
                <img :src="courseInfo.cover">
            </el-upload>
        </el-form-item>

        <el-form-item label="课程价格">
            <el-input-number :min="0" v-model="courseInfo.price" controls-position="right" placeholder="免费课程请设置为0元"/> 元
        </el-form-item>
        <el-form-item>
            <el-button :disabled="saveBtnDisabled" type="primary" @click="saveOrUpdate">保存并下一步</el-button>
        </el-form-item>
    </el-form>



  </div>
</template>

<script>
import course from '@/api/edu/course'
import subject from '@/api/edu/subject'
import Tinymce from '@/components/Tinymce' //引入组件
export default {
  //声明组件
  components:{Tinymce},
  data() {
    return {
        saveBtnDisabled: false, // 保存按钮是否禁用
        courseInfo:{
            title: '',
            subjectId: '', //二级分类ID
            subjectParentId:'', //一级分类ID
            teacherId: '',
            lessonNum: 0,
            description: '',
            cover: '/static/01.jpg',
            price: 0
        },
        teacherList:[], //用于封装教书数据
        subjectOneList:[], //一级分类
        subjectTwoList:[], //一级分类
        BASE_API:process.env.BASE_API, //接口API地址
        courseId:'' //课程ID
    }
  },
  created() {
      this.init()
    
  },
  watch:{ //监听
      $route(to,from){  //路由变化的方式,路由发生变化,方法就会执行
          this.init()
      }  
  },
  methods: {
      init(){
        //获取到路由中的Id值
        if(this.$route.params && this.$route.params.id){
            this.courseId=this.$route.params.id
            //调用根据Id查询课程的方法
            this.getInfo()
        }else{
            this.courseInfo={subjectId: '', cover: '/static/01.jpg',lessonNum: 0,price: 0}
            //初始化讲师
            this.getListTeacher()
            //初始化一级分类
            this.getOneSubject()            
        }
      },
      //根据课程Id查询
      getInfo(){
        course.getCourseInfoId(this.courseId)
            .then(response => {
                //在courseInfo课程基本信息,包含一级分类id 和 二级分类id
                this.courseInfo = response.data.courseInfoVo
                //1. 查询所有的分类,包含一级和二级
                subject.getSubjectList()
                    .then(resposne =>{
                        this.subjectOneList = resposne.data.list;
                        //把所有的一级分类数组进行遍历,比较当前courseInfo里面一级分类id和所有的一级分类id
                        for(var i=0;i<this.subjectOneList.length;i++){
                            //获取每个一级分类
                            var oneSubject = this.subjectOneList[i]
                            //比较当前courseInfo
                            if(this.courseInfo.subjectParentId == oneSubject.id){
                                //获取一级分类所有的二级分类
                                this.subjectTwoList = oneSubject.children
                            }
                        }
                    })
                    //初始化讲师
                    this.getListTeacher()
            })
      },
      //上传之前调用的方法
      beforeAvatarUpload(file){
            const isJPG = file.type === 'image/jpeg'
            const isLt2M = file.size / 1024 / 1024 < 2
            if (!isJPG) {
                this.$message.error('上传头像图片只能是 JPG 格式!')
            }
            if (!isLt2M) {
                this.$message.error('上传头像图片大小不能超过 2MB!')
            }
            return isJPG && isLt2M
      },
      //上传封面成功
      handleAvatarSuccess(res,file){
          this.courseInfo.cover = res.data.url
      },
      //点击某个一级分类,触发事件,显示对应的二级分类
      subjectLevelOnChanged(value){
          //value 就是一级分类的id
          //遍历所有的分类,包含一级和二级
          for(var i=0;i<this.subjectOneList.length;i++){
              //每个一级分类
              var oneSubject = this.subjectOneList[i]
              //判断:所有的一级分类和点击的一级分类是否一样
              if(value === oneSubject.id){
                  //从一级分类获取里面的所有二级分类
                 this.subjectTwoList = oneSubject.children
                 //把二级分类id值清空
                 this.courseInfo.subjectId=''
              }
          }
      },
    //查询所有一级分类
    getOneSubject(){
       subject.getSubjectList()
            .then(response => {
                this.subjectOneList = response.data.list
            })
    },
    //查询所有的讲师
    getListTeacher(){
        course.getListTeacher()
            .then(response =>{
                this.teacherList = response.data.items;
            })
    },
    //添加课程
    addCourse(){
        course.addCourseInfo(this.courseInfo)
            .then(response => {
                //提示
                 this.$message({
                    type:'success',
                    message:'添加课程信息成功'
                 })
                 this.$router.push({ path: '/course/chapter/'+response.data.courseId })
            })
    },
    //修改课程
    updateCourse(){
        course.updateCourseInfo(this.courseInfo)
            .then(response => {
                //提示
                 this.$message({
                    type:'success',
                    message:'修改信息成功!'
                 })
                 //跳转到第二步
                  this.$router.push({ path: '/course/chapter/'+this.courseId})
            })
    },
    saveOrUpdate() {  
       //判断是修改还是添加
       if(!this.courseInfo.id){
           //添加
           this.addCourse()
       }else{
           this.updateCourse()
       }
    }
  }
}
</script>

<style scoped>
.tinymce-container {
  line-height: 29px;
}
</style>